package com.datasentinel.util;

import java.util.zip.Checksum;


/******************************************************************************
*
* Jacksum version 1.7.0 - checksum utility in Java
* Copyright (C) 2001-2006 Dipl.-Inf. (FH) Johann Nepomuk Loefflmann,
* All Rights Reserved, http://www.jonelo.de
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*
* E-mail: jonelo@jonelo.de
*
*****************************************************************************/


public class CRC64 implements Checksum
{

	// CRC-64 look-up table
	private static final long[] crc64tab = new long[] { 0x0000000000000000L, 0x01b0000000000000L, 0x0360000000000000L,
			0x02d0000000000000L, 0x06c0000000000000L, 0x0770000000000000L, 0x05a0000000000000L, 0x0410000000000000L,
			0x0d80000000000000L, 0x0c30000000000000L, 0x0ee0000000000000L, 0x0f50000000000000L, 0x0b40000000000000L,
			0x0af0000000000000L, 0x0820000000000000L, 0x0990000000000000L, 0x1b00000000000000L, 0x1ab0000000000000L,
			0x1860000000000000L, 0x19d0000000000000L, 0x1dc0000000000000L, 0x1c70000000000000L, 0x1ea0000000000000L,
			0x1f10000000000000L, 0x1680000000000000L, 0x1730000000000000L, 0x15e0000000000000L, 0x1450000000000000L,
			0x1040000000000000L, 0x11f0000000000000L, 0x1320000000000000L, 0x1290000000000000L, 0x3600000000000000L,
			0x37b0000000000000L, 0x3560000000000000L, 0x34d0000000000000L, 0x30c0000000000000L, 0x3170000000000000L,
			0x33a0000000000000L, 0x3210000000000000L, 0x3b80000000000000L, 0x3a30000000000000L, 0x38e0000000000000L,
			0x3950000000000000L, 0x3d40000000000000L, 0x3cf0000000000000L, 0x3e20000000000000L, 0x3f90000000000000L,
			0x2d00000000000000L, 0x2cb0000000000000L, 0x2e60000000000000L, 0x2fd0000000000000L, 0x2bc0000000000000L,
			0x2a70000000000000L, 0x28a0000000000000L, 0x2910000000000000L, 0x2080000000000000L, 0x2130000000000000L,
			0x23e0000000000000L, 0x2250000000000000L, 0x2640000000000000L, 0x27f0000000000000L, 0x2520000000000000L,
			0x2490000000000000L, 0x6c00000000000000L, 0x6db0000000000000L, 0x6f60000000000000L, 0x6ed0000000000000L,
			0x6ac0000000000000L, 0x6b70000000000000L, 0x69a0000000000000L, 0x6810000000000000L, 0x6180000000000000L,
			0x6030000000000000L, 0x62e0000000000000L, 0x6350000000000000L, 0x6740000000000000L, 0x66f0000000000000L,
			0x6420000000000000L, 0x6590000000000000L, 0x7700000000000000L, 0x76b0000000000000L, 0x7460000000000000L,
			0x75d0000000000000L, 0x71c0000000000000L, 0x7070000000000000L, 0x72a0000000000000L, 0x7310000000000000L,
			0x7a80000000000000L, 0x7b30000000000000L, 0x79e0000000000000L, 0x7850000000000000L, 0x7c40000000000000L,
			0x7df0000000000000L, 0x7f20000000000000L, 0x7e90000000000000L, 0x5a00000000000000L, 0x5bb0000000000000L,
			0x5960000000000000L, 0x58d0000000000000L, 0x5cc0000000000000L, 0x5d70000000000000L, 0x5fa0000000000000L,
			0x5e10000000000000L, 0x5780000000000000L, 0x5630000000000000L, 0x54e0000000000000L, 0x5550000000000000L,
			0x5140000000000000L, 0x50f0000000000000L, 0x5220000000000000L, 0x5390000000000000L, 0x4100000000000000L,
			0x40b0000000000000L, 0x4260000000000000L, 0x43d0000000000000L, 0x47c0000000000000L, 0x4670000000000000L,
			0x44a0000000000000L, 0x4510000000000000L, 0x4c80000000000000L, 0x4d30000000000000L, 0x4fe0000000000000L,
			0x4e50000000000000L, 0x4a40000000000000L, 0x4bf0000000000000L, 0x4920000000000000L, 0x4890000000000000L,
			0xd800000000000000L, 0xd9b0000000000000L, 0xdb60000000000000L, 0xdad0000000000000L, 0xdec0000000000000L,
			0xdf70000000000000L, 0xdda0000000000000L, 0xdc10000000000000L, 0xd580000000000000L, 0xd430000000000000L,
			0xd6e0000000000000L, 0xd750000000000000L, 0xd340000000000000L, 0xd2f0000000000000L, 0xd020000000000000L,
			0xd190000000000000L, 0xc300000000000000L, 0xc2b0000000000000L, 0xc060000000000000L, 0xc1d0000000000000L,
			0xc5c0000000000000L, 0xc470000000000000L, 0xc6a0000000000000L, 0xc710000000000000L, 0xce80000000000000L,
			0xcf30000000000000L, 0xcde0000000000000L, 0xcc50000000000000L, 0xc840000000000000L, 0xc9f0000000000000L,
			0xcb20000000000000L, 0xca90000000000000L, 0xee00000000000000L, 0xefb0000000000000L, 0xed60000000000000L,
			0xecd0000000000000L, 0xe8c0000000000000L, 0xe970000000000000L, 0xeba0000000000000L, 0xea10000000000000L,
			0xe380000000000000L, 0xe230000000000000L, 0xe0e0000000000000L, 0xe150000000000000L, 0xe540000000000000L,
			0xe4f0000000000000L, 0xe620000000000000L, 0xe790000000000000L, 0xf500000000000000L, 0xf4b0000000000000L,
			0xf660000000000000L, 0xf7d0000000000000L, 0xf3c0000000000000L, 0xf270000000000000L, 0xf0a0000000000000L,
			0xf110000000000000L, 0xf880000000000000L, 0xf930000000000000L, 0xfbe0000000000000L, 0xfa50000000000000L,
			0xfe40000000000000L, 0xfff0000000000000L, 0xfd20000000000000L, 0xfc90000000000000L, 0xb400000000000000L,
			0xb5b0000000000000L, 0xb760000000000000L, 0xb6d0000000000000L, 0xb2c0000000000000L, 0xb370000000000000L,
			0xb1a0000000000000L, 0xb010000000000000L, 0xb980000000000000L, 0xb830000000000000L, 0xbae0000000000000L,
			0xbb50000000000000L, 0xbf40000000000000L, 0xbef0000000000000L, 0xbc20000000000000L, 0xbd90000000000000L,
			0xaf00000000000000L, 0xaeb0000000000000L, 0xac60000000000000L, 0xadd0000000000000L, 0xa9c0000000000000L,
			0xa870000000000000L, 0xaaa0000000000000L, 0xab10000000000000L, 0xa280000000000000L, 0xa330000000000000L,
			0xa1e0000000000000L, 0xa050000000000000L, 0xa440000000000000L, 0xa5f0000000000000L, 0xa720000000000000L,
			0xa690000000000000L, 0x8200000000000000L, 0x83b0000000000000L, 0x8160000000000000L, 0x80d0000000000000L,
			0x84c0000000000000L, 0x8570000000000000L, 0x87a0000000000000L, 0x8610000000000000L, 0x8f80000000000000L,
			0x8e30000000000000L, 0x8ce0000000000000L, 0x8d50000000000000L, 0x8940000000000000L, 0x88f0000000000000L,
			0x8a20000000000000L, 0x8b90000000000000L, 0x9900000000000000L, 0x98b0000000000000L, 0x9a60000000000000L,
			0x9bd0000000000000L, 0x9fc0000000000000L, 0x9e70000000000000L, 0x9ca0000000000000L, 0x9d10000000000000L,
			0x9480000000000000L, 0x9530000000000000L, 0x97e0000000000000L, 0x9650000000000000L, 0x9240000000000000L,
			0x93f0000000000000L, 0x9120000000000000L, 0x9090000000000000L };

	private long value;
	private long length;

	public CRC64()
	{
		value = 0;
		length = 0;
	}

	public void reset()
	{
		value = 0;
		length = 0;
	}

	public void update(byte b)
	{
		value = (value >>> 8) ^ crc64tab[(int)((value ^ b) & 0xff)];
		length++;
	}

	public void update(int b)
	{
		update((byte)(b & 0xFF));
	}

	public byte[] getByteArray()
	{
		long val = getValue();
		return new byte[] { (byte)((val >> 56) & 0xff), (byte)((val >> 48) & 0xff), (byte)((val >> 40) & 0xff),
				(byte)((val >> 32) & 0xff), (byte)((val >> 24) & 0xff), (byte)((val >> 16) & 0xff),
				(byte)((val >> 8) & 0xff), (byte)(val & 0xff) };
	}

	public long getLength()
	{
		return length;
	}
	
	@Override
	public long getValue()
	{
		return value;
	}

	public void update(byte[] b)
	{
		update(b, 0, b.length);
	}
	
	@Override
	public void update(byte[] b, int off, int len)
	{
		for(int i = 0; i < len; ++i)
		{
			update(b[i + off]);
		}
	}

	/*

	  Testcases:
	  according to http://swissknife.sourceforge.net/CRC64.html
	  "IHATEMATH" -> E3DCADD69B01ADD1

	  and according to the Python Cookbook, 2nd Edition, Oreilly
	  Recipe 2.30. Calculating CRC-64 Cyclic Redundancy Checks
	  "IHATEMATH" -> E3DCADD69B01ADD1

	  jacksum -a crc64 -X -q TXT:IHATEMATH
	  E3DCADD69B01ADD1        9

	  jacksum -a crc64 -X -q 49484154454D415448
	  E3DCADD69B01ADD1        9


	  according to the CRC64 poly, http://sf.net/projects/jcrcgen
	  "123456789" -> 46A5A9388A5BEFFE

	  jacksum -a crc64 -X -q TXT:123456789
	  46A5A9388A5BEFFE        9

	  jacksum -a crc64 -X -q 313233343536373839
	  46A5A9388A5BEFFE        9

	 */
}
